This invention relates to a fluid distribution system and process, useful in applications such as manufacturing semiconductor materials and devices.
In the semiconductor manufacturing field, trimethylsilane (3MS) and other liquefied compressed gases such as dichlorosilane, arsine and phosphine have been widely used or are currently emerging as important precursors for low dielectric constant (low k) materials in the fabrication of capacitors, memory cells and other microelectronic device structures.
As used herein, the term xe2x80x9clow pressurexe2x80x9d refers to pressure levels below about 1500 torr, the term xe2x80x9cliquefied compressed gasesxe2x80x9d refers to fluids that are in liquid form at 25xc2x0 C. and the term xe2x80x9clow pressure compressed liquefied gasxe2x80x9d refers to fluids that are in liquid form at 25xc2x0 C. at pressure  less than 100 psig.
The challenge attending the use of these liquefied compressed gas materials is to provide safe and efficient storage and delivery to the tools of such liquefied compressed gases. An additional challenge encountered is the need to provide high purity materials within the semiconductor industry. Contaminants within these liquefied compressed gas materials can lead to defects within the semiconductor device. Defects translate directly into reduced product yield and reduced profits. As an illustration, 3MS is a low pressure compressed liquefied gas with a vapor pressure of xcx9c12 psig at room temperature.
Due to its flammability, toxicity and its potential fluid release or spill, 3MS cylinders or other supply vessels containing the liquefied compressed gas cannot be installed inside the semiconductor manufacturing facility (fab) in large quantity.
In consequence, the source vessel for the 3MS liquid is required to reside outside the fab. When it is in use, the 3MS is drawn from the outside vessel through associated flow lines into the fab, where it flows to the semiconductor manufacturing tool. Such 3MS can be vaporized after withdrawal in liquid form from the vessel, or the withdrawn fluid can be vapor, as drawn off from a vapor phase overlying the liquid in the supply vessel.
Since the vapor pressure of the liquefied compressed gas is quite low at room temperature, and can be affected by the environmental temperature at the (outside the building) storage site, it is difficult to achieve a reasonably high flow rate (e.g., 6 standard liters per minute, slpm) in conventional flow lines during cold weather conditions.
In addition, condensation in the vapor delivery lines adversely affects the flow stability, and causes undesirable fluctuations in the desired line pressure and volumetric flow rate of the vapor deriving from the liquefied compressed gas. Condensation in the tool can in some instances cause or require tool shutdown.
These are substantial problems that severely impact the use of liquefied compressed gases in the semiconductor manufacturing industry.
Corresponding problems attend the use of liquefied compressed gases in other industrial processes.
The present invention relates to a fluid distribution system and process, useful in applications such as manufacturing semiconductor materials and devices.
In one aspect, the invention relates to a fluid supply system for supplying fluid to a point-of-use fluid-consuming unit, such system comprising:
a main fluid supply vessel;
a local supply vessel, containing a physical sorbent having affinity for the fluid;
first flow circuitry interconnecting the main fluid supply vessel and the local supply vessel, with a pressure regulator in at least one of the first flow circuitry and the main fluid supply vessel, so that fluid is flowed into the local supply vessel at pre-determined pressure; and
second flow circuitry coupling the local supply vessel with said fluid-consuming unit, arranged so that fluid is dispensed from the local supply vessel through the second flow circuitry to the fluid-consuming unit.
Another aspect of the invention relates to a low pressure compressed liquefied gas supply system, for supply of corresponding gas to a point-of-use gas-consuming unit, such system comprising:
a main liquid supply vessel;
a local supply vessel, containing a physical sorbent having affinity for gas deriving from the liquefied compressed gas;
first flow circuitry interconnecting the main liquid supply vessel and the local supply vessel, a sub-atmospheric pressure regulator in at least one of the first flow circuitry and the main liquid supply vessel, so that gas deriving from the liquefied compressed gas is flowed into the local supply vessel at sub-atmospheric pressure;
second flow circuitry coupling the local supply vessel with the gas-consuming unit, arranged so that gas is dispensed from the local supply vessel through the second flow circuitry to the gas-consuming unit.
A still further aspect of the invention relates to a process for supplying a fluid to a fluid-consuming operation, comprising:
providing a main fluid supply unit;
providing a local supply unit coupled in fluid flow communication with the main fluid supply unit, such local supply unit comprising a physical sorbent having affinity for the fluid;
flowing fluid from the main fluid supply unit on demand to the local supply unit, to maintain fluid in the local supply unit; and
discharging fluid from the local supply unit to the fluid-consuming unit, wherein fluid flow from the main fluid supply unit to the local supply unit is selectively regulated in the fluid flow communication between the main fluid supply unit and local supply unit, or in the main supply unit.
Other aspects, features and embodiments in the invention will be more fully apparent from the ensuing disclosure and appended claims.